Subnetting Tutorial for Beginners Part 4: A Subnetting Challenge

In this tutorial, we are going to take all the learning’s we have done in part 1, 2 and 3 and we will combine them all to solve this cool challenge. In this challenge we will apply all the subnetting concepts to subnet a test network IP address. Try to do this challenge yourself. If you get stuck somewhere you can take help from the solution presented in this guide.

The Challenge

Consider the following IP address scheme:

192.168.1.0/24

Task:

Create an IP addressing scheme with more than 1 network address that can support 40 devices per subnet.

Solution:

Let’s look at the different possibilities you can have with the current IP scheme:

Subnet Mask in DecimalSubnet Mask in BinaryCIDR NotationNetworksHosts / Network
255.255.255.011111111.11111111.11111111.00000000/242 ^ 0 = 1254
255.255.255.12811111111.11111111.11111111.10000000/252 ^ 1 = 2126
255.255.255.19211111111.11111111.11111111.11000000/26462
255.255.255.22411111111.11111111.11111111.11100000/27830
255.255.255.24011111111.11111111.11111111.11110000/281614
255.255.255.24811111111.11111111.11111111.11111000/29326
255.255.255.25211111111.11111111.11111111.11111100/30642
255.255.255.25411111111.11111111.11111111.11111110/311281

Looking at the table, 192.168.1.0/26 seems to be the perfect fit for our use case. The subnet mask will be 255.255.255.192. This network can support 4 subnets and 62 hosts per subnet.

Determine Addresses for Each Subnet

Now, if you remember, we need to determine the following for each of the subnets in our network:

  • Network Address
  • Broadcast Address
  • First available host address
  • Last available host address

Address: 192.168.1.0 /26

Subnet Mask: 255.255.255.192 = /26

Hosts / Net = 62

First Subnet

Network Address (Set all host bits to 0) -> 192.168.1.0 /26 -> 11000000.10101000.00000001. 00 000000

Broadcast Address (Set host bits to 1) -> 192.168.1.63 -> 11000000.10101000.00000001. 00 111111

First Host (Add one) -> 192.168.1.64 -> 11000000.10101000.00000001. 00 000001

Last Host (Subtract one) -> 192.168.1.62 -> 11000000.10101000.00000001. 00 111110

Second Subnet

Network Address (Set all host bits to 0) -> 192.168.1.64 /26 -> 11000000.10101000.00000001. 01 000000

Broadcast Address (Set host bits to 1) -> 192.168.1.127 -> 11000000.10101000.00000001. 01 111111

First Host (Add one) -> 192.168.1.65 -> 11000000.10101000.00000001. 01 000001

Last Host (Subtract one) -> 192.168.1.126 -> 11000000.10101000.00000001. 01 111110

Third Subnet

Network Address (Set all host bits to 0) -> 192.168.1.128 /26 -> 11000000.10101000.00000001. 10 000000

Broadcast Address (Set host bits to 1) -> 192.168.1.191 -> 11000000.10101000.00000001. 10 111111

First Host (Add one) -> 192.168.1.129 -> 11000000.10101000.00000001. 10 000001

Last Host (Subtract one) -> 192.168.1.190 -> 11000000.10101000.00000001. 10 111110

Fourth Subnet

Network Address (Set all host bits to 0) -> 192.168.1.192 /26 -> 11000000.10101000.00000001. 11 000000

Broadcast Address (Set host bits to 1) -> 192.168.1.255 -> 11000000.10101000.00000001. 11 111111

First Host (Add one) -> 192.168.1.193 -> 11000000.10101000.00000001. 11 000001

Last Host (Subtract one) -> 192.168.1.254 -> 11000000.10101000.00000001. 11 111110

This is how you can create subnets based on the current IP scheme. You can practice it by using different classes of IP addresses and get better at this.

Related Guides

Subnetting Tutorial Part 1

Subnetting Tutorial Part 2

Subnetting Tutorial Part 3

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About the Author: Umair

A self-learned Javascript developer specializing in Frontend and Backend frameworks including React.js, Redux, Node.js, Express, MongoDB. He has extensive industry experience as a Tech Support lead and System Administrator. Currently learning Web3, (Solidity, Hardhat, Ethers.js) Smart contracts development, testing and auditing.

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